This invention generally relates to apparatus and a method for closing cartons, and more particularly, to a flange folding method and apparatus effective for folding down marginal flanges attached to upstanding carton sides to enable secure lid placement on the carton.
Commercially available frozen foods, such as ice cream, are packaged in cartons impervious to water vapor and odors. Such cartons are usually fabricated of plastic coated paperboard preformed to include four sides, a bottom panel and a hinged top cover having depending flanges overlying the top portion of the sides.
A new form of carton for ice cream or the like has a removable paperboard lid. Short vertical flanges are provided along the upper sides of the walls of the carton. When folded down along the margins of the carton mouth, the separate lid covering the mouth engages the flanges to seal the contents.
The process of automatically filling and preparing this new form of carton presents a unique flange folding problem to be solved. Specifically, after the erected cartons are filled with food product, the side flanges must be prebroken and folded down so that the cartons are ready to receive the lids immediately after filling. Especially where the cartons are filled with a liquid product, it is highly desirable to fold the flanges as gently as possible to avoid potential spillage of the product. Furthermore, if the flanges are not properly and fully prebroken, the lid resists proper seating on the carton. When improper seating engagement between the lid and the carton occurs, the process must be interrupted and valuable production time is lost.
Carton folding apparatus are known for use in folding down flanges on a carton. The prior art devices generally require a long series of rollers or plowing blades pressing against the flange as the carton moves along a conveyor. There is little or no control of the fold line of the carton resulting in deleterious outward or inward bowing of the carton sides or flange buckling. The resulting improper flange folding may hinder lid placement on the carton mouth or improper seating engagement, which may result in spillage, carton rejection and/or machine interruption.